Slam fire with apex comp spring kit

[jpm2953]

So, what I have is a 1.0 M&P full size 9mm.

it has the apex competition spring kit w/ sear in it. It has the old style 1/16" sear block housing. When my buddy installed this kit, he didn't upgrade the sear block housing so he is using the original small sear spring.

He apparently dropped the slide to chamber a round and the gun fired into the door of his safe. Is this possible? I thought the striker block would have prevented this? I have the gun with me now. I was going to mill out the sear block for the larger diameter spring and see if I can get it to duplicate the issue.

[jpm2953]

update #1. I dropped the slide about 100 times before I took it apart and it never "dropped the hammer" I was able to pull the trigger everytime afterwards and it dropped the striker. I took the pistol apart and the striker block seems to work properly.  I couldn't get the striker to hang in the forward position nor could I push it forward without pressing on the SB.

The gun actually had the 1/8" diameter sear spring already in it... I guess he didn't know the difference between 1/16 and 1/8. I still went ahead and put a factory sear spring in it per his request.

 

Probably gonna call apex today and see what they think. I'm beginning to think his finger was on the trigger and he just didn't notice.

[jpm2953]

update #2. Sent Apex an email and they called me yesterday afternoon. They said they all talked about it for 30 min and they can't come up with any explanation other than he had his finger on the trigger.

[M1A4ME]

My M&P 9MM FS is a first gen.  I had trigger issues (took two fingers and pulling it towards the right side to get it to release the striker).  Brand new, should have sent it back, didn't - ordered an APEX CAEK kit and installed it and fell in love with the trigger (as compared to the original even when it was working).

 

A couple years later I got into failure to fire issues.  Ended up being timing and sear flutter (small dent on the primer  when the striker was hitting the striker block after the trigger was pulled=timing) or no dent in the primer (sear flutter let the striker go forward with the slide when it chambered the next round).

 

What I'm saying is, even when the striker wasn't caught by the sear it never went off.  I was getting that for 3 to 4 rounds from every magazine.  About 20 to 25 percent of the time I had a failure to fire.  My finger is on the trigger when the slide goes forward to pick up the next round and chamber it (I'll bet every one else still has the trigger back after firing, too).

 

I'd think, based on the design and my experiences that he'd have had to let up on the trigger (if his finger was holding it back) when he chambered the round to get it to reset, and then pulled it again to make if fire.

 

Just a guess, but I don't think I read about people having this issue with the Gen 1 M&P's.  Just terrible lousy triggers, poor accuracy, reliability issues, etc.

[superslowmo]

Chances are his finger was on the trigger. It happens more than people think, and most that do have an ND don’t even realize it was their actions that caused it.


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